The involvement of endogenous brain rhythms in speech processing

Endogenous brain rhythms are at the core of oscillation-based neurobiological theories of speech. These brain rhythms have been proposed to play a crucial role in speech segmentation, attention allocation, and the temporal and spectral processes involved in speech perception. Despite the strong theoretical foundations of oscillatory models, direct empirical evidence for their involvement in speech processing remains limited, partly due to the challenge of distinguishing endogenous rhythms from responses to external stimuli. We review prominent oscillation-based theories (dynamic attending, active sensing, asymmetric sampling in time, and segmentation theories) and the supporting empirical evidence from electrophysiological and brain stimulation studies. Finally, we suggest potential directions for future research that could clarify the contributions of endogenous rhythms to speech processing.